skip to main content
Main Site Navigation
Top of main content

What Is Irritable Bowel Syndrome (IBS)?

IBS is a common digestive disorder that affects about 20% of people in the United States, mostly women. It affects how the large intestine (colon) works.

Food moving through the digestive tract passes from the small intestine to the colon. The main function of the colon is to absorb water. Muscles in the colon usually contract in a way that pushes stool (waste products) through. In IBS, these muscle contractions may be abnormal. Too many contractions may cause diarrhea. Slowed or fewer contractions may cause constipation. Irregular or intermittent (spasmodic) muscle contractions may cause pain or a feeling of urgent need to move the bowels (go to the bathroom).

What Causes IBS?

The cause is unknown but appears to be related to the nervous system. People with IBS have a colon that reacts very strongly to signals from the brain. Many people find that stress, anxiety, and emotional upset trigger symptoms. Certain foods or eating too much or too little may also cause the colon to overreact.

What Are the Symptoms of IBS?

The most common symptoms are pain in the abdomen (belly), bloating, and constipation or diarrhea or both. Other symptoms include an urgent need to move the bowels and feeling of incomplete evacuation. These symptoms come and go over days, weeks, or months.

How Is IBS Diagnosed?

Not everyone who has gastrointestinal symptoms has IBS. The health care provider diagnoses IBS by taking a careful medical history to detail the symptoms. No test can prove that someone has IBS. The health care provider may use blood tests, x-rays, and looking at the colon through a thin, flexible tube (special instrument called an endoscope) to rule out other disorders.

How Is IBS Treated?

Lifestyle changes may help relieve IBS symptoms. These changes include eating a high-fiber diet, avoiding foods that make symptoms worse, eating regular meals that are not too big, drinking enough water, getting regular exercise, and reducing stress.

Several medicines are available for IBS. The health care provider can help decide which are best. Over-the-counter laxatives should be taken only under a doctor’s direction, because overuse of laxatives may be harmful. Tranquilizers and antidepressants may also help people with IBS.

DOs and DON’Ts in Managing IBS:

  • DO learn what foods worsen your symptoms and avoid them.
  • DO eat a good diet with high-fiber foods, including whole grains, fruits, and vegetables. Fiber supplements may help if your diet does not have enough fiber.
  • DO eat regular, balanced meals.
  • DO drink plenty of water to help the colon work correctly.
  • DO take medicines as instructed by your health care provider.
  • DO exercise. Try to do 30 minutes of moderate physical activity daily.
  • DO try to lower stress. Don’t take on more work or obligations than you can handle.
  • DON’T take over-the-counter laxatives without a health care provider telling you to do so.
  • DON’T skip meals.
  • DON’T eat large meals or high-fat meals.

Contact the following sources:

  • American Academy of Family Physicians
    Tel: (913) 906-6000
  • American Gastroenterological Association
    Tel: (301) 654-2055
  • American College of Gastroenterologists
    Tel: (703) 820-7400

Copyright © 2016 by Saunders, an imprint of Elsevier, Inc.

Ferri’s Netter Patient Advisor

Not sure which type of care is right for you?

We can help.